List of devices

An air conditioner is a device that changes the temperature of air that goes through it. Most airconditioners are for cooling air down. They work either by evaporating water inside them to make the air cool the same way that sweating cools you off, or they work by transferring heat from inside to outside by a heat pump. Some airconditioners are called reverse cycle because they can be used to heat your house too.

An alarm clock is a special type of clock that makes a sound or other kind of alert at a set time to wake someone or remind them to do something. It usually has a display or hands to show the time, buttons for setting the alarm, and a switch to turn the alarm on or off. People tend to keep them by their bedside.

extension An aperture is an opening that lets something pass through, such as light, air, or sound. In a camera, it is the adjustable opening inside the lens. Its size controls how much light reaches the camera sensor and also affects how much of the picture looks sharp.

A wide aperture lets in more light and can make the background look blurry. A narrow aperture lets in less light and keeps more of the scene clear. The word comes from a Latin word meaning "an opening".

An axle is a shaft that goes through the center of a wheel, which the wheel rotates around.
One axle may have only one wheel or many wheels on it. Axles generally only have two wheels on them, one at each end.

A battery is a device that stores electricity. Things that have batteries still need power to run, but you don't have to plug them in to a power point in your house. When a battery runs out of power, you need to get a new battery or recharge your old one.

Binoculars, also called field glasses, are a special kind of glasses that function like two small telescopes, one for each eye. They let you see things in the distance as if they are much closer. Binoculars are smaller and easier to use than a telescope, and are more pleasant to use as you do not need to close one eye to look through binoculars.

A bung is a stopper or lid for casks, barrels or flasks.

A camera is a device that is used to take photos, like the ones you see on every page in this dictionary.

A cellphone is another name for a mobile telephone, a small phone that doesn't need to be plugged into a fixed telephone line and can be carried virtually anywhere.

A chock is a piece of wood or metal used to hold something steady. Chocks are most often used against wheels to stop a vehicle from rolling away.